Conduit clips and, in particular, those used for the support of electrical conduit have long been used in the construction industry. As an example, the assignee of this application, Erico Products, Inc., manufactures and sells what is known in the trade as a Caddy.RTM. 8-12M conduit clip. The clip is formed from spring steel and is generally U-shaped in overall configuration. The clip has two spring legs adapted to engage differently sized conduit. The legs terminate in inner and outer foot sections extending toward and overlapping each other when the clip is closed. The inner foot section has a longitudinally bent locking tab which engages the apex of either of two longitudinally spaced triangular holes in the outer foot section depending on the diameter of the conduit being supported.
A conduit clip of similar description is also manufactured by Minerallac Electric Company. This clip includes a guide channel between two holes for channeling the locking tab between the first hole and the second hole to secure conduit of different diameters. The tab bends of both fasteners run longitudinally of the foot such that the bent tab extends in a plane longitudinally of the foot. A locking tab edge surface is thus formed on one foot for engaging the apex of the locking holes of the other foot.
A somewhat similar but more complex clip using two longitudinally bent tabs and paired sets of holes is sold by B-Line. Such complex clip is seen in U.S. Pat. No. 4,958,792. In all of the above fasteners, the tabs tend to form a burr in tension parallel to the grain of the steel creating a potential weak point. Moreover, the tabs project substantially beyond the clip and tend to catch on many things, such as workers' gloves, clothing, etc.
Also, such fasteners generally need to be closed with channel lock pliers and, in some cases, with at least two adjustments of the pliers. Such offset pliers require substantial clearance, limiting how close the fasteners may be positioned, and also causing a torsional twist which may make the fastener difficult to close.
Thomas Industries, Inc. has sold a locking conduit/pipe clip which also is generally U-shaped. It differs from the aforementioned clips in that a locking tab is employed which is bent inwardly from the outer locking foot on which it is carried. Further, the bend permitting the formation of the tab extends generally transversely of the clip such that a transversely extending tab is formed. The tab enters either of two locking openings on an inner locking foot and extends toward a pipe which is clamped within the clip. However, twisting or bending of the conduit may cause the fastener to open.
There is a need to provide a clip fastener which will close around conduits without either foot extending beyond the fastener legs when smaller conduits are being secured. There is a need to provide unobtrusive gripping points or dimples on a fastener leg to enable the clip to be closed easily by finger pressure or with slip-joint pliers.
There is also a need to eliminate sharp protrusions on the perimeter of a conduit clamp. It is further desirable that a locking tab be provided with improved locking strength. There is also a need to provide a clip which tends to center the conduit in the fastener and which additionally increases the strength of the fastener against opening due to loading.